If this dosn't get posted here moderators please let me know where it goes...

I have two machines running seti@home, my main computers, a windows quad core and a linux dual core machine.

I am thinking about making some kinda crazy construction with old computers just for seti@home...

Can anyone who has done a bunch of machines let me know about their experiences?

Have a big empty cellar, would like to do 10 or 20 (or 50) machines running seti@home.

Please let me know of anyone's experiences doing so...
I am interested in how much the electric bill goes up per machine...
I am also interested in any stories, experiences, or wisdom on doing
something like this from those who have done so...

(from someone who has done this) ... Your better bet, on a WU per watt ratio is to invest in a modern multi core machine , stuff it with economically priced gpus and let it rock.
I ran as many as 12 old machines at once for several months and my best rac was 2500 and I was consuming 22kwh a day

My newish I7 860 and two gtx 460 gpu pulls a solid 20,000 all by itself. It draws a hearty but much more economical 8 kwh

Yes perhaps from an electric standpoint I'd be better off with quad core machines and just forget the pile of old pcs I have sitting around collecting dust. Most of those machines are 1ghz-2ghz single core machines.

I'm a bit confused by the gpu thing. If I understand correctly, does this mean I can just plug a bunch of extra video cards with fast gpus into each machine I plan to use for seti@home/boinc? How many video cards can I jam into each machine?

Older rigs can do a decent job if supplied with GPUs to do most of the work.
Not sure I would crank up a single core rig. But I do still have my first core2 duo running at 2.93Ghz supporting a 560 and a 470. It has a 30K RAC, and does not run 24/7.
Bringing a bunch of single core rigs online using the CPUs only will mostly get you amazing power bills, not a great RAC.Always remember.....kitties are all Angels with fur.
'Cat lives matter.'

Thanks for your thoughts guys. I think I will just add one more modern machine to my current setup. Something like a quad core with 4 or 5 gpus I think would be best way to increase my output alot, without my power bill skyrocketing.

I have very little experience with gpu computing. If I got a quad core machine with say a good nvidia gpu card that is pci-express for main video...

What do I do about the gpu cards? say the machine has 4 pci slots... Can I just get 4 pci gpu cards, plug them in and be good to go?

That would be kinda cool, a quad core machine with 5 gpus means 9 processors cranking away on projects... I think that could increase my output alot.

Any thoughts or advice on this I would greatly appreciate. I think I'll be doing
an ebay fundraiser, selling off spare parts in order to pay for this new box.

If you have just restarted SETI then your RAC will need time to build that back up again (anything up to 8wks or so) but now compare your Quad against mine (I take it that yours is a Q6600 too), Computer 5712423, (though with the recent server problems its RAC is about 2K down), and you'll likely realise that a better GPU or 2 will help you along by a large margin. ;)

I have very little experience with gpu computing. If I got a quad core machine with say a good nvidia gpu card that is pci-express for main video...

What do I do about the gpu cards? say the machine has 4 pci slots... Can I just get 4 pci gpu cards, plug them in and be good to go?

That would be kinda cool, a quad core machine with 5 gpus means 9 processors cranking away on projects... I think that could increase my output alot.

Regret having to be skeptical, but that sounds very ambitious for a start in gpu computing. There are some cards that run on pci slots, but they aren't very powerful, and you run into issues when the cards in the system are not fairly comparable. The less powerful cards may constrain what you can do with the powerful one, etc. Think 5 is too ambitious to start with. You'll also run into power supply constraints and heat problems. I'll let others get more specific if you're interested in pursuing something like this.Another Fred
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There is my main computer... Maybe I should just add gpu cards to this and my
dual core linux box?

Steven

Upgrading your current GPU to something more efficient would be a good first step.

Loading up a few machines with 3 or 4 high end GPU's is probably the most efficient. However you will have to invest in high capacity power supplies & cooling. With single, or maybe dual, GPU's per machine you can use more run of the mill components.

With a large multiGPU system the CPU is less important. As you may be using it only to run the OS and feed the GPU's. So you could go with a lower cost CPU.

When adding these systems you just have to decide on how much power you are willing to pay for to run them. The UPS's I have in a rack show a usage of about 400 kW/h per week for only about a third of my machines. So it is probably safe to say I'm using around 5,000 kW/h per month running all of the systems. I don't know what the rate we pay for electric at work is, but my home rate is about $0.18 per kW/h.SETI@home classic workunits: 93,865 CPU time: 863,447 hours Join the BP6/VP6 User Group today!

If you want serious crunching power, GPU is the only way to go. The CPU is not that important. Things to have in mind are power consumption, heat management and GPU spacing.

Power
Choose the GPU that gives you the most FLOPS for your budget, and check what it will cost on the electricity bill. You can check this comparison for those numbers.

You have to have a power supply that can supply all the power the GPU(s) need, plus about 150 watts for the rest of the computer. But remember that running a power supply at close to 100% capacity is a sure way to get a short life span, get a much larger power supply than what you need.

Heat
Heat kills eletronics. High end GPU:s often move the heated cooling air outside the computer chassi, others just whisks the air around while passively cooled GPU:s doesn't move the heat away at all. Plan the airflow in the box, use extra fans if necessary. Get a temperature monitoring program, like GPU-Z, to make sure you don't overheat.

Spacing
High end GPU:s often require dual slots. Check the motherboard slot spacing what fits your motherboard. Also, single slot spacing might not be beneficial to airflow.

I kinda meant add gpus as my extra hobby funds allow... I don't think I can afford to buy another machine and 4 gpu cards all at once, but I can get a machine, wait a bit, buy a gpu card, wait a bit, and so on...

Thanks for everyones advice, would love to have a powerful system to increase my output for the project.

I kinda meant add gpus as my extra hobby funds allow... I don't think I can afford to buy another machine and 4 gpu cards all at once, but I can get a machine, wait a bit, buy a gpu card, wait a bit, and so on...

Thanks for everyones advice, would love to have a powerful system to increase my output for the project.

Best regards,

Steven

Not too many motherboards have enough slots for 4 GPUs, and many cases would not have enough room on the back panel for them.

You'll have to research this carefully before proceeding.

I only have one rig running 3 GPUs, and that one is laying flat, no case.
All the others only have 2 due to case limitations, although they do have enough slots for 3.Always remember.....kitties are all Angels with fur.
'Cat lives matter.'